1. Field of the Invention
The present invention relates to an electronic equipment having a plurality of heat-emitting semiconductor parts in which a refrigerant such as air, or the like, flows to cool the semiconductor parts by means of heat sinks. More particularly, the invention relates to an electronic equipment having the feature of the cooling structure, such as the heat sinks.
2. Description of the Related Art
Conventionally, the following system is often employed in an electronic equipment as a means of cooling a plurality of heat-emitting semiconductor parts mounted on a circuit substrate such as a printed substrate, a ceramic substrate, or the like. A fin is mounted on each of the heat-emitting semiconductor parts, thereby supplying cooling air to the sides of the semiconductor parts which are then sequentially cooled. However, since the amount of heat emitted from the semiconductor parts continues to significantly increase, the above system presents a new problem in that the air temperature thus soars, and accordingly, in the further the position of the equipment in the downstream direction of the air, the more the cooling performance deteriorates. Thus, in order to solve the above problem, the following method has been proposed. A fin is mounted on each of the heat-emitting semiconductor parts and the cooling air supplied from a blower is blown into each of the fins through a plenum and a nozzle, or the like, disposed on each of the fins. Then, the air which has been made warm in each of the fins is recovered in a discharge duct and then discharged therefrom. Such a method is disclosed in, for example, Japanese Utility Model Unexamined Publication No. 1-73993. A cooling equipment of such a conventional electronic equipment will be described with reference to FIG. 13.
A plurality of heat-emitting LSIs 102 are mounted on a substrate 101. A heat sink 103 is further disposed on each of the LSIs 102. The cooling air is then supplied to each of the LSIs 102 from an inlet opening 106, through a blow duct 104 and an ejection opening 105, thereby cooling the LSIs 102. After cooling the LSIs 102, the cooling air stream is inverted in each of the heat sinks 103 and drawn into by a fan from into feedback openings 108 provided for discharge ducts 107 so as to be discharged via outlet opening 10 to the exterior of the equipment.
The ejection openings 105 and the feedback openings 108 are separated from the heat sinks 103. Further, the discharge ducts 107 and the flow ducts 104 are mounted on the heat sinks 103 in two stages.
In the above conventional electronic equipment, when the amount of heat emitted from the semiconductor parts and the mounting density thereof are relatively small, all the cooling air can be substantially transferred to the heat sinks without any leakage, and all the air discharged from the heat sinks can be substantially recovered from the feedback openings and discharged to the exterior of the equipment. However, recently, the processing speed of electronic equipment has become higher and the density thereof has become larger, thereby increasing the amount of heat emitted from the semiconductor parts and the mounting density thereof and further increasing the air flow rate, thus raising the ejection pressure thereof and the discharge pressure from the heat sinks. Hence, the air discharged from the heat sinks may be leaked from a gap between each of the heat sinks and the feedback openings, thus making it difficult to recover the discharge air from the feedback openings without any leakage. It makes the matter worse that the unrecovered air is warm and thus increases the temperature of the other semiconductor parts or makes the air stream complicated, thereby increasing the flow loss and thus hampering efficient air cooling performed on the electronic equipment.
Moreover, in the conventional electronic equipment, the discharge ducts are disposed on the top of the heat sinks provided for the semiconductor parts mounted on the substrate, and the blow ducts are further disposed on the top of discharge ducts. When the electronic equipment is constructed as described above, a considerably large space is required on top of the heat sinks. There is no problem when the semiconductor chips are arranged in a plane having a sufficiently large space on top of the heat sinks. However, when a plurality of substrates are three-dimensionally disposed closely parallel to each other, a sufficiently large space cannot be provided on top of the heat sinks, thus making it difficult to arrange the ducts constructed as described above.